enter image description hereThis is a 17 yr old double wide mobile home. Our plan is to use existing 240V wiring, kill one of the lines and connect the other to a new 20A breaker to make a 20A 120V for the gas range.

I've never noticed this before but I've never seen anything like it. Two 40A brekers, I assume a separated double pole, for the range straddles the 30A dryer breaker? It's obviously designed this way since there's a bracket hooking the two switches together. Any idea why, or any cautions for me? Thanks in advance! enter image description here

enter image description here

  • Aha .... I've determined that this is QT (quad breaker), I didn't know they existed! So, I should be ok to remove it and put the 30A on a double pole breaker and add a 20A breaker for the range outlet ...... yes?? – JimInAlabama Aug 20 '20 at 15:49
  • Does this answer your question? diy.stackexchange.com/questions/110151/… – Nate S. Aug 20 '20 at 15:49

This is a quadplex breaker. Basically, in order to squeeze more stuff into breaker panels, many manufacturers came up with a way to squeeze two breakers into one space. The problem is that for 240V loads that doesn't work - you end up with 0V between the pair of breakers instead of 240V! So then they came up with quadplex - 4 breakers in 2 spaces. The inner 2 and the outer 2 are each 240V pairs, just like traditional double breakers.

I am not a breaker expert, but that looks to me like it may be "handle tie" rather than a true functional double breaker. Actually, the "All poles have no common trip" reinforces that the breakers are independent of each other, electrically speaking.

That is OK for some situations (MWBC), but if I am correct then that was never actually correct for a 240V circuit such as an oven. That being said, it doesn't matter if you are changing things anyway.

There are two possibilities here for your current (yes, pun intended) situation. You may be able to swap individual breakers, or you may have to deal with them as a set of 4 (quadplex). If they are individuals then you can pick one of the two 40A breakers and replace it with a 20A breaker. Based on the latest picture, the circuit is using neutral, so you can swap either breaker and leave the white neutral as-is. If the new gas range is hardwired, then you should be all set. If it has a plug and you are installing a 20A receptacle, you will likely need to pigtail the 8 AWG wires to 10 or 12 AWG wire to connect to the receptacle, as many can't handle 8 AWG wire.

Make sure the breakers are correct for the panel. There are a lot of similar breakers from different brands. The wrong ones might fit but won't fit correctly.

Also, in case it wasn't clear already, you can't replace a quadplex with two pairs of duplex breakers if even one of the pairs still needs 240V.

  • 1
    You are correct, there is no common trip here, making this breaker illegal for both range and dryer. – Harper - Reinstate Monica Aug 20 '20 at 16:10
  • manassehkatz-Moving 2 Codidact, thanks a lot for your help. And pardon my layman's ignorance but I want to be sure I understand. So, if the two 40's on the outside are separate from the inside 30A's (meaning that they are not all four built in together?), I leave the 30A's as is, disconnect both 40A's, add a 20A, Rewire the 20A and mark the white as you described, and wire nut the end of the red wire and identify what it was with tape....yes?? – JimInAlabama Aug 20 '20 at 17:59
  • Actually, my talk about colors may not be correct. Assuming "not conduit", your colors could be: black to one breaker, white to the other breaker. In which case the white should have been marked as a hot (colored tape) and now that color comes off, white goes to neutral, black to new breaker. Or it could be black/red/white - black & red to breakers, white to neutral. In which case black to new breaker, red capped, white stays on neutral. But key (which the panel experts would know, I do not) is whether you can swap some of the breakers or whether this has to be entire quadplex replaced. – manassehkatz-Moving 2 Codidact Aug 20 '20 at 18:06
  • Ahh, thanks. BTW I added another picture to my original post and it appears that they are individual pieces. And it is black and red to the breakers. – JimInAlabama Aug 20 '20 at 18:09

One fatal flaw in the existing setup is that the circuit breaker is labeled

 All poles have
 no common trip

That makes them unfit to feed either a dryer or range -- both those loads are 240V loads with a neutral wire, and as such, they do require common trip. They would be acceptable for an air conditioner or water heater, which do not have neutral.

If you can find an appropriate 20-30-20 quadplex (which is to say: one with common trip in the middle), you could drop this in to replace the existing breaker, and change sockets and pigtail as needed to put your gas range on one of the 20's.

  • For A/C or heater (or any 240V-only appliance), wouldn't common trip still be a good thing? If there is a massive overcurrent situation then both will trip. But if it is marginal - mildly overcurrent for a while - you could have one trip just before the other would have tripped. User goes to panel, flips both (handle tie) off/on. Unit starts up and trips again quickly but still only one side - user assumes "must be all off" and takes off cover of appliance to work on it...and zaps on the untripped hot. (Though he should have flipped both to a clear OFF...) – manassehkatz-Moving 2 Codidact Aug 20 '20 at 17:55
  • The flip side (pun intended) is that there aren't too many 30A or 40A 120V loads, so a 40/30 quad must be for something, and MWBC don't fit since those are typically 15 & 20, so must be for 30 & 40 240V loads. Just doesn't make much sense to me. – manassehkatz-Moving 2 Codidact Aug 20 '20 at 17:57
  • I can't thank you guys enough! Harper - Reinstate Monica, Home Depot actually has the QT 20 30 20 in stock locally, I added a picture of it. Inside 30A poles have common trip, two single pole outsides. I think this is what I need yes? And an afterthought question, the breaker in there now has no common trip, did they assume that the ties would throw both if one tripped?? – JimInAlabama Aug 20 '20 at 19:11

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